1. Field of the Invention
The present invention relates in general to apparatus for automatically taking up slack in a system where wear occurs and in particular to a brake caliper system where the wear on the friction material used for braking action causes a misadjustment of the brakes and in which the present invention automatically compensates for the wear of the friction material forming the brake pads.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
It is well known in the prior art that in braking systems in particular where brake pads are applied to a rotating surface that wear of the brake pad material occurs thus causing a change in the distance the pads must move before engaging the brake surface creating less available brake application force and an increase in brake application time.
It is also well known, as for instance, in automobile brake applications, that automatic adjusting devices have been developed that attempt to compensate for wear of the brake pad material.
This problem is especially noticeable in systems where large amounts of braking force must be applied. For instance, in oil field equipment, huge drums carrying thousands of feet of cable lifting pipe strings weighing hundreds of tons must have giant disc brakes where tons of force are applied to the brake pads to brake or lock the drum against enormous weights that are attempting to rotate the drum. In such cases, the brakes are checked frequently and, when excessive wear is detected, the gap between the brake shoe and the rotating drum disc is manually adjusted to provide the proper gap so that proper braking action can occur.
It would be advantageous to have an automatic adjusting system that would compensate for a predetermined wear of the disc pad material and provide the appropriate gap between the brake pad material and the rotating disc surface forming part of the drum that carries the weight of the cable and drill string.